not that i actually want to encourage the practice but i dont actually have a problem with tranny being used to refer to a transmission if and only if its not being used as a double entendre ive heard people use it far more often than not solely as an abbreviation without any other meaning attached this may be related to my profession which has a large number of abbreviations which are entirely inappropriate to say as anything except as abbreviations but again i would never encourage it theres too many clueless people who would hear it and take that as permission to make shitty jokes that harm trans people in the long run